Vehicle odometer tampering is a growing problem in the automotive industry. Traditionally, odometer tamperers have rolled back mechanical odometers to substantially reduce the displayed odometer mileage. This criminal effort was counteracted by designing mechanical odometers which would only roll in a positive direction, thus disabling reverse rolling which would reduce the displayed odometer mileage. However, criminals learned to remove the cluster assembly from the vehicle, and rolled back the mechanical odometers by partially disassembling the odometer.
Digital odometers were initially immune from odometer tampering, but in recent years clever criminals have developed methods of entering the memory location of the microcontroller which operates the digital odometers and altering the stored odometer mileage. This is typically accomplished by removing the cluster assembly and accessing the microcontroller electronically for altering the stored odometer mileage. Alternatively, criminals have infiltrated the cluster control module microcontroller by simply plugging into the vehicle diagnostics system and penetrating any electronic security barriers.
Accordingly, it is desirable to provide a method of preventing odometer tampering in vehicles having microcontrollers which electrically communicate with non-volatile memory locations for storing the odometer reading.